#mindmap {
    width: 100%;
    height: 100vh;
    position: relative;
  }
  
  .node {
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    width: 200px;
    height: 200px;
    background-color: #fff;
    border: 1px solid #000;
    border-radius: 5px;
    text-align: center;
    line-height: 200px;
    font-size: 24px;
  }
  
  .node:hover {
    background-color: #ccc;
  }
  
  .line {
    position: absolute;
    width: 1px;
    height: 100%;
    background-color: #000;
  }